This invention relates to a sling hook and, more particularly, to a sling hook equipped with a curved slot in the sleeve portion to facilitate installation by twisting rather than threading as is conventional.
The hook with which the instant invention is concerned is advantageously employed in conjunction with wire rope to support loads for movement from one place to another--as in loading of ships, land vehicles, in logging, etc. The sling hook is a unitary member having a curved bill at one end and a sleeve or wire rope receiving passageway at the other, illustrated generally in U.S. Pat. Nos. 2,381,531 and 4,073,042.
Although the art workers have tried for many years to avoid the laborious threading operation (wherein the end of the rope is threaded through the eye of the sleeve--see, for example, U.S. Pat. Nos. 1,420,487 and 1,572,347--the commercial art has remained static and tolerated these difficulties. For example, the hook sleeve portion must be threaded onto the rope before the rope ends are fashioned into eyes or loops. Notwithstanding the great advantage of being able to have the eyes or loops formed in the ends of the wire rope at an earlier time and at a different place from the installation of the hook, the art has put up with this disadvantage.
Another factor always present in the mind of the user is the safety or integrity of the hook. Should either the hook or rope fail, there is the possibility of great injury (as well as property damage). Prior art hooks have been characterized by the lack of any way of quickly establishing whether the hook has been stressed beyond its yield point and thus is potentially unsafe.
The instant invention overcomes these disadvantages by introducing a curved slot into the sleeve portion of the hook in such a way as to make possible a twisting rather than a threading installation of the wire rope and which is so constructed and arranged to divide the sleeve portion into a pair of unequal lug eyes. This results in an unusual and unexpected strength in the overall hook--load testing establishing that the hook ultimately fails in the shank or bill portion as in the conventional hook, and not in the split sleeve portion. More particularly, the provision of this single change from the prior art, results in two beneficial results--ease of the installation and a visual indication of overstressing.
Other objects and advantages of the invention may be seen in the details of the ensuing specification.